TOKYO, Japan (CNN) -- A man ran over a group of people with his truck and then stabbed 18, killing at least 7, in a video game district of downtown Tokyo Sunday afternoon, according to a Tokyo fire official.

The dead included five men -- three aged 19, 47 and 74 -- and a woman, according to a Tokyo metropolitan police officer. The gender of the seventh person was not immediately known. Eleven others were wounded, police said, with two critically injured.

"The suspect told police that he came to Akihabara to kill people," Jiro Akaogi, a spokesman for the Tokyo Metropolitan Police Department, told The Associated Press.

"He said he was tired of life. He said he was sick of everything," Akaogi added.

Authorities said the man drove a rented truck into a crowd, jumped from the vehicle and then began stabbing the people he had knocked down, AP reported.

Japanese media reported that the suspect told investigators he was 25 years old.

Nearly 20 ambulances rushed to the scene, with television footage showing rescue workers tending to victims in the street.

The Akihabara district, where the attack took place, specializes in electronic gadgets and video games and is popular with people interested in comic books and distinctive fashion.